package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
)

func Login(w http.ResponseWriter, r *http.Request) {
	var creds Credentials
	err := r.ParseMultipartForm(0)
	if err != nil {
		log.Printf("Error parsing form: %v", err)
		http.Error(w, "Bad Request", http.StatusBadRequest)
		return
	}

	log.Println(r.FormValue("username"))
	creds.Username = strings.ToLower(r.FormValue("username"))
	creds.Password = r.FormValue("password")

	// Retrieve the hashed password from the database
	hashedPassword, userExists := getUserFromDatabase(creds.Username)
	if !userExists {
		errorMessage := creds.Username + " does not exist"
		log.Println(errorMessage)
		w.WriteHeader(http.StatusUnauthorized)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": "Incorrect username or password",
		})
		return
	}

	// Compare the stored hashed password with the provided password
	err = bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(creds.Password))
	if err != nil {
		errorMessage := "Incorrect username or password"
		log.Println(errorMessage)
		w.WriteHeader(http.StatusUnauthorized)
		json.NewEncoder(w).Encode(map[string]interface{}{
			"error": errorMessage,
		})
		return
	}

	// Create a new session token
	sessionToken := uuid.NewString()
	expiresAt := time.Now().Add(sessionLength)

	// Store the token in the session map
	sessions[sessionToken] = session{
		username: creds.Username,
		expiry:   expiresAt,
	}

	// Set the session token as a cookie
	http.SetCookie(w, &http.Cookie{
		Name:    "session_token",
		Value:   sessionToken,
		Expires: expiresAt,
	})

	log.Printf("User logged in: %s", creds.Username)

	// Send JSON response indicating successful login
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(map[string]interface{}{
		"message": "Login successful",
	})
}

func getUserFromDatabase(username string) (string, bool) {
	var hashedPassword string
	err := db.QueryRow("SELECT password FROM users WHERE username = $1", username).Scan(&hashedPassword)
	if err == sql.ErrNoRows {
		// User not found
		return "", false
	} else if err != nil {
		log.Printf("Error retrieving user from the database: %v", err)
		return "", false
	}

	return hashedPassword, true
}

func getUserUUID(username string) (string, error) {
	var uuid string
	err := db.QueryRow("SELECT uuid FROM users WHERE username = $1", username).Scan(&uuid)
	if err != nil {
		if err == sql.ErrNoRows {
			// User not found
			return "", fmt.Errorf("user not found: %s", username)
		}
		return "", err
	}
	return uuid, nil
}

func Logout(w http.ResponseWriter, r *http.Request) {
	// Get the session token from the request cookies
	sessionCookie, err := r.Cookie("session_token")
	if err != nil {
		log.Printf("Error getting session cookie: %v", err)
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	sessionToken := sessionCookie.Value

	// Remove the user's session from the session map
	delete(sessions, sessionToken)

	log.Printf("User logged out")

	// Set the user's `session_token` cookie to an empty value and an immediate expiry time
	http.SetCookie(w, &http.Cookie{
		Name:    "session_token",
		Value:   "",
		Expires: time.Now(),
	})

	// Redirect to the index page
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func Signup(w http.ResponseWriter, r *http.Request) {
	// Check if the request method is POST
	if r.Method == http.MethodPost {
		var creds Credentials
		err := r.ParseMultipartForm(0)
		if err != nil {
			log.Printf("Error parsing form: %v", err)
			http.Error(w, "Bad Request", http.StatusBadRequest)
			return
		}

		creds.Username = strings.ToLower(r.FormValue("username"))
		creds.Password = r.FormValue("password")
		name := r.FormValue("name")
		email := r.FormValue("email")
		// Check if the username is already taken
		if _, userExists := getUserFromDatabase(creds.Username); userExists {
			log.Printf("Username already exists: %s", creds.Username)
			http.Error(w, "Username Already Taken", http.StatusConflict)
			return
		}

		// Hash the user's password
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(creds.Password), hashCost)
		if err != nil {
			log.Printf("Error hashing password: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		// Generate a UUID for the user
		userUUID := uuid.New()

		// Store the user in the database with the generated UUID
		if err := insertUserIntoDatabase(creds.Username, string(hashedPassword), string("normal"), userUUID.String(), name, email); err != nil {
			log.Printf("Error inserting user into database: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		// Create a new session token
		sessionToken := uuid.NewString()
		expiresAt := time.Now().Add(sessionLength)

		// Store the token in the session map
		sessions[sessionToken] = session{
			username:    creds.Username,
			expiry:      expiresAt,
			sessionUUID: userUUID.String(),
		}

		// Set the session token as a cookie
		http.SetCookie(w, &http.Cookie{
			Name:    "session_token",
			Value:   sessionToken,
			Expires: expiresAt,
		})

		log.Printf("User signed up and added to database: %s", creds.Username)

		createUserFolder(creds.Username)

		// Redirect to the new user page
		http.Redirect(w, r, "/welcome", http.StatusSeeOther)
		return
	}

}